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There have been a lot of threads around the A8 failures. There was also a Poll. Thought it might be good to create a Google Sheet to track this stuff, could be good for Ask Tadge at some point or some other way to get data to GM in regards to the failures.
Open to suggestions on structure, I can handle making those adjustments. But this sheet is open to all for editing, so if your Forum User name is not listed, you can add it. If it is listed, you can update your response if needed.
There is a chart tab as well that has some data based on the April Poll results, but this will update with new data of course.
REPEAT: BEFORE UPDATING THE SPREADSHEET: Please search for your user ID, if it is already there, update that row. If not, you can add yourself to the end.
I have done some searching on the internet about what the new procedure GM will come out with next year to resolve the shudder problem with the 8 speed transmission. I have found some information from people who claim they have inside information that GM will come with a new fluid and a new procedure to flush the fluid. The below information is from the GM techlink website and it seems to support that, I highlighted it in red at the end of the article.
My car already had the fluid flushed about a month ago and it did NOT solve the problem, hopefully the new procedure they come out with next year will fix it for good.
John
Changes in Transmission Oil Cooler Flush Requirements
Recent GM studies have shown that automatic transmission oil cooler flush requirements have limited benefit on many current transmission repairs. Based on the studies, GM will no longer require a mandatory flush and flow test of the transmission oil cooler and the oil cooler pipes — including the auxiliary transmission oil cooler, if equipped — to be performed in every instance of transmission or torque convertor replacements or internal transmission repairs. (Fig. 1) As a result of this policy change, transmission repairs will be simpler, the environmental impact of waste oil will be reduced and Global Warranty Management transaction processing will be simplified.
Fig. 1
Transmission Repair Policy Changes
Effective December 1st, 2018:
Job cards will no longer require a transmission flush code from the DT-45096 Transmission Oil Cooling System Flush and Flow Test Tool (DT-45096 TransFlow®machine). (Fig. 2)
The Flush Code field in Global Warranty Management related to all applicable transmission labor operations should be left blank. The field will be eliminated mid-December.
The Warranty Support Center will no longer require a flush code on warranty transactions.
Repair procedures in the Service Information will be updated to reflect the elimination of the transmission cooler flush requirement. In addition, related service bulletins, the labor time guide, and the GM Service Policies and Procedures Manual will be updated accordingly.
Fig. 2
The DT-45096 TransFlow machine continues to be a valuable GM Essential Tool that should be used when diagnosing transmission overheating conditions or a transmission failure due to a lack of lubrication. Technicians should continue to document the TransFlow code in the correction comments of the job card in instances when the DT-45096 flow test procedure is used to diagnose an overheating or lubrication concern.
TIP: Use only the appropriate GM automatic transmission fluid when performing a transmission repair. If the fluid in the DT-45096 TransFlow machine is different than what is used in the transmission, after performing the flush and flow test, use compressed air to blow the residual transmission fluid out of the transmission oil cooler and lines.
New Fluid Exchange Procedure
A new repair procedure for the DT-45096 TransFlow machine to exchange fluid also has been developed to address torque converter clutch shudder on 8L45 and 8L90 8-speed automatic transmissions (RPOs M5T, M5N, M5U, M5X). The new transmission fluid exchange procedure and new formula of Mobil 1 Synthetic LV ATF HP transmission fluid is being rolled out regionally due to the limited availability of both the new transmission fluid and tool kit. It is anticipated that the new transmission fluid and tool kit will be available nationwide by late January or early February 2019. Look for more information to be released soon in a service bulletin and the December 2018 Emerging Issues seminar (10218.12V).
I'll update it soon. My 2017 started shuddering at 3200 miles.
Triple flush took care of the problem, but I'm keeping the Range unit plugged in for now.
Update done. Thanks
Last edited by ddelallata; 06-08-2017 at 10:55 PM.
Just an suggestion for the graph above. Since you have "No Failure" and then two columns that break out the failures, add a column of Combined Failures next to No Failures.
Yes, good idea. I showed "Date of Failure" as the date in shop, not when first symptom noticed. Symptoms were sporadic at first, then in Nov. 2016 started to get worse and could be demonstrated at any time.
Thanks for the updates folks, I'll be doing some cleanup of things after people update; remove duplicates, data format consistency, stuff like that.
Once we can get some of the previous folks to update dates and mileage info we can start to see if there are any trends.
So far, as mentioned by others previously, it really seems to show that the issue is more with the torque converter than the transmission, failure rates on those seem to be much greater. And most of those seem to be with the 2015's at this point.
I added a column for model (Stingray / Z51 / Grand Sport / Z06) so if you get a chance, pop back in there and update. And some of the columns have drop downs to enter data, just click on the little arrow and you can pick from the list.
Last edited by mountainears; 06-09-2017 at 11:41 AM.
So far, as mentioned by others previously, it really seems to show that the issue is more with the torque converter than the transmission, failure rates on those seem to be much greater. And most of those seem to be with the 2015's at this point.
Would the delayed engagement (o-ring) problems described in #16-NA-014 be considered a problem with the transmission? They wouldn't be linked to the TC, IMO.
Thanks for the updates folks, I'll be doing some cleanup of things after people update; remove duplicates, data format consistency, stuff like that.
Once we can get some of the previous folks to update dates and mileage info we can start to see if there are any trends.
So far, as mentioned by others previously, it really seems to show that the issue is more with the torque converter than the transmission, failure rates on those seem to be much greater. And most of those seem to be with the 2015's at this point.
Even the 2017 reported failure rate according to those data is around 15%. Now granted, it's probable that people with no problems likely reported less than those with, but even cutting that number down to 5% is way too high for a single component in a modern vehicle.
I think this is a good idea - will still have some bias, but should provide a more accurate picture than anything we've done so far.
I'll look at this and fill in my part later this weekend. Several forum members, including me, have had (or do have) more than one C7. Will this allow us to put both experiences into the database?
Also, some might fill out the database as 'no failure' now, but will want to update later if they have an issue. Will this allow that scenario?
If that is the case, append a - 1 and a - 2, etc., to your forum name and list each one separately. This way I won't prune you out of there as a duplicate like I have already for some I have seen listed twice.
Originally Posted by Hopper12
I think this is a good idea - will still have some bias, but should provide a more accurate picture than anything we've done so far.
I'll look at this and fill in my part later this weekend. Several forum members, including me, have had (or do have) more than one C7. Will this allow us to put both experiences into the database?
Also, some might fill out the database as 'no failure' now, but will want to update later if they have an issue. Will this allow that scenario?
I'm on an iPad and looks like it's prompting me to download an app to respond to the spreadsheet. I doubt I'll do that so I'll just add that I've got a 2015 with 7,800 miles A8 and when it's cold I always use paddles till it warms up but no failure yet.
Would the delayed engagement (o-ring) problems described in #16-NA-014 be considered a problem with the transmission? They wouldn't be linked to the TC, IMO.
Bingo.
FYI iclick, an o-ring issue is not necessarily the problem with the delayed engagement. GM's stance is that the TC is leaking down due to the veins in the stator support plate not having adequate check ***** to stop fluid drain back. the result is delayed engagement while the TC fills and pressurizes.
The actual fix for the stator shaft replacement is not an o-ring, but complete replacement of the stator support plate as changes in the casting were made a new part released to facilitate an additional check ball. As part of the change, normal seals/orings etc are changed out for good measure per the TSB.
There needs to be the following change to the overall structure IMHO:
1. Failure is a strong word, and can be interpreted quite differently. For example, some may interpret as a complete replacement of the Torque converter or transmission. I would reword to "Issue'' or "problem", and define as a dealer acknowledged issue, not just "i think there is an issue".
2. Although my TC is failing as well, my main issue at this current moment is the delayed engagement as mentioned above. It's hard to classify as a failure of either as the exact issue has not even been identified by GM yet (the current fixes do not work). At best it's an issue related to the transmission, not the TC as previously thought by the braintrust.
Last edited by \Boost Monkey/; 06-09-2017 at 12:53 PM.
06-08-2017, 06:37 PM
A8 Transmission failure tracking
Fig. 1
Fig. 2
Excellent! 
